ML12243A435

8/30/2012 Meeting RR 48 - Phased Array Ultrasonic Examination in Lieu of Radiography

ML12243A435
Person / Time
Site:	Palo Verde
Issue date:	08/30/2012
From:	Hansen D Arizona Public Service Co
To:	Plant Licensing Branch IV
Gibson L
References
Download: ML12243A435 (23)

Text

Requestq for Relief 48 Phased Array Ultrasonic Examination in lieu of Radiography Ari ona P Arizona Publicblic Service Ser ice Compan Company Douglas Hansen Sr Consulting Engineer & Level III

Agenda

• Applicable codes

• R li f R Relief Requestt 48 Scope S

• Reason for Relief Request 48

• Code Case N-659-2

• Paragraph summary comparison (Attachment 2 of Relief Request)

P /T h i

• Process/Technique V Validation lid ti

• Sample comparison graphics

• Conclusion

Applicable Codes

• Construction Code ASME III

• 1974 Edition, Winter 1975 Addenda

• Repairs/Replacements

• ASME XI 2001 Edition, 2003 Addenda

Scope

• ASME Class 2 piping circumferential butt welds

• Carbon steel base and weld metal

• Thickness > 0.337

• Diameters > 6 NPS

• Geometry shall allow 100% coverage

• Weld and 1/2 1/2 base metal on each side

• PVNGS Units 1, 2 and 3 for the 3rd interval

• Unit 1 thru 7-17-2018

• Unit 2 thru 3-17-2017

• Unit 3 thru 1-10-2018

Reason for Request

• Personnel - using Phased Array Ultrasonic Examination Technique (PAUT) reduces:

• Exposure risk

• Dose

• Crew size

• Outage - using PAUT:

• Reduces time for results

• Reduces impact to the schedule

• Allows adjacent work to proceed

• Reduces risk ((errors)) associated with starting/stopping/rescheduling critical activities

• Quality - using PAUT:

• Increases critical flaw detection

• Provides flaw depths for repairs

• Recorded data for reviews and retention

Code Case N-659-2 Inquiry: Under what conditions and limitations may an ultrasonic examination be used in lieu of radiography where radiography is required by NB-5200, NB 5200, NC-5200, ND-5200, WB-5200 or WC-5200, and substitution of ultrasonic examination would not otherwise be permitted?

Reply: It is the opinion of the Committee that all welds may be examined using the ultrasonic (UT) method in lieu of the radiographic (RT) method, provided that all of the following requirements are met:

N-659-2 (a) Examination Area

• Additional restrictions:

• 100% coverage (in all 4 directions)

• Weld ground flush

• Surface examination (PT or MT)

S f Surface EExam A-B AB 1/2 1/2 A B C D PAUT Exam Volume A-B-C-D

N-659-2 (b) Examination Procedure

• Additional restrictions:

• ASME Section V Article 4; 2001 Edition, 2003 Addenda

• PAUT with minimum of 40-70 degrees

• Volume scanned with 0 degree N 659 2 (c)

N-659-2 ( ) Procedure P d D Demonstrationt ti

• Additional restrictions:

• Demonstration for each nominal diameter and thickness

• Essential and non-essential requirements documented

N-659-2 (d) Qualification Blocks

• Additional restrictions:

• For each nominal diameter and thickness N-659-2 6 9 2 (e) ( ) Materials i l

• Additional restrictions:

• None; cast and austenitic products are not included N-659-2 (f) Examination Plan

• Additional restrictions:

• None; an exam plan and sketch will be provided

N-659-2 (g) Acceptance Criteria

• Additional restrictions:

• ASME Section III; 2001 Edition, 2003 Addenda

N-659-2 (h) Pre-Service Examinations

• Additional restrictions:

• Pre-Service Examinations (PSE) will be performed, when required, in addition to the proposed PAUT examinations N-659-2 (i & j) Acquisition

• Additional restrictions:

• None, examinations will be auto (encoded) and recorded N-659-2 (k) Acquisition Personnel

• Additional restrictions:

None for acquisition personnel; they will be qualified and

• None, trained using the same demonstrated equipment

N-659-2 (k) Analysis Personnel

• Additional restrictions:

• They will demonstrate their capability to detect and characterize flaws; will utilized data acquired with the demonstrated procedure; and:

• Detection

• ASME XI Table VIII-S2-1

• Flawed grading units will be 1/4 longer than actual flaw

• Unflawed grading units will be a min of 1

• At least 2 of the flaws will meet N-659-2 (d) sizes

• Sizing

• Flaws will be sized as being >

actual length Fl

• Flaws will ill b be properly l

categorized as surface or subsurface

N-659-2 (l) ANII

• Additionall restrictions:

Additi t i ti

• None; review and acceptance of the ANII N 659 2 (m) Other Requirements N-659-2

• Additional restrictions:

• None; other related requirements will be met N-659-2 (n) Repairs

• Additional restrictions:

• None; flaws will be repaired and the weld re-examined N-659-2 (o) Code Case

• Additional restrictions:

• None; the Case number will be recorded

Process/Technique Validation

• PVNGS developed a set of actual weld flawed specimens

• Flaws totaled over 60 for Carbon Steel

• Porosity

• Incomplete fusion

• Incomplete penetration

• Slag

• Cracking

• S Specimens i h have been b radiographed di h d for f comparison i

• Specimens are being digital radiographed for additional comparison

Process/Technique Validation Process/Technique Validation RESULTS

• PAUT detected all the RT indicated flaws

• PAUT detected several additional areas of incomplete fusion

• PAUT detected all of the cracks in the exam volume

14-100-CS SLAG RT ~1 length PAUT ~1 length

8-120-CS Incomplete Fusion RT ~1 intermittent PAUT ~1

~1 length

12-100-CS Incomplete Penetration RT ~ 3/4 length PAUT ~3/43/4 length

(~1.2 in other direction)

8-120-CS Porosity RT ~1 length PAUT ~1 length

10-60-CS ID Crack (PT)

RR 48 Summary

• Additional restrictions (requirements) to N-659-2:

• Automated (encoded) Phased Array Ultrasonic Examination

• All welds will receive a surface (PT or MT) examination

• Weld caps will be ground flush

• Volume will be scanned in all 4 directions

• 100% coverage

• Volume will be scanned with a 0 degree

• Demonstration for each nominal diameter and thickness

• Data will be recorded for analysis and retention

• PSE will be in addition and per ASME Section XI

Conclusion RR 48 utilizes as a basis Code Case N-659-2 RR 48 requires additional restrictions RR 48 provides an acceptable level of quality and safety